Large-Scale Space-Based Solar Power Station: Multi-Scale Modular Space Power

ABSTRACT

A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom is provided. Each solar power station includes a plurality of satellite modules. The plurality of satellite modules each include a plurality of modular power generation tiles including a photovoltaic solar radiation collector, a power transmitter and associated control electronics. The power transmitters can be coordinated as a phased array and the power generated by the phased array is transmitted to one or more power receivers to achieve remote wireless power generation and delivery. Each satellite module may be formed of a compactable structure capable of reducing the payload area required to deliver the satellite module to an orbital formation within the space-based solar power station.

RELATED APPLICATION

This application claims priority to U.S. provisional patent applicationSer. No. 61/993,016 entitled “Large-Scale Space-Based Array: Packaging,Deployment and Stabilization of Lightweight Structures,” filed on May14, 2014; U.S. provisional patent application Ser. No. 61/993,025entitled “Large-Scale Space-Based Array: Multi-Scale Modular Space PowerSystem,” filed on May 14, 2014; U.S. provisional patent application Ser.No. 61/993,957 entitled “Large-Scale Space-Based Array: Modular PhasedArray Power Transmission,” filed May 15, 2014; U.S. provisional patentapplication Ser. No. 61/993,037 entitled “Large-Scale Space-Based Array:Space-Based Dynamic Power Distribution System,” filed May 14, 2014; U.S.provisional patent application Ser. No. 62/006,604 entitled “Large-ScaleSpace-Based Array: Efficient Photovoltaic Structures for Space,” filedJun. 2, 2014; and U.S. provisional patent application Ser. No.62/120,650 entitled “Large-Scale Space-Based Array: Packaging,Deployment and Stabilization of Lightweight Structures,” filed Feb. 25,2015, all of which are incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION

The present invention is related to a space-based solar power stationincluding a plurality of solar power satellite modules, morespecifically to a modular space-based power station with a plurality ofcompactable independent solar power satellite modules flown in anorbital formation that by themselves or in unison form a phased and/oramplitude array at radio frequencies for power transmission from spaceto Earth, each module having a plurality of power generation tileshaving integrated photovoltaic cells, antennas, thermal radiator andcontrol circuits in varying configurations.

BACKGROUND

Space-based solar power (SBSP) describes the collection of solar powerin space by a solar-power satellite or a satellite power system (SPS)and then the conversion and transmission of the power to a remotereceiver for conversion back to electrical power. In an SBSP system,solar energy is collected as electrical energy on board, powering somemanner of wireless power transmission to a receiver located remotelyfrom the SBSP. The wireless power transmission application might includea microwave transmitter or laser emitter, which would direct its beamtoward a collector, such as a power receiving rectenna at the remotelocation, such as, on the Earth's surface.

SBSP differs from ground-based solar collection methods in that themeans used to collect energy resides on an orbiting satellite instead ofon the Earth's surface. Basing such a system in space results in ahigher collection rate for the solar energy due to the lack of adiffusing atmosphere. In a conventional ground-based system a largepercentage (55-60%) of the solar energy is lost on its way through theatmosphere by the effects of reflection and absorption. Space-basedsolar power systems convert solar energy to a far-field emission such asmicrowaves outside the atmosphere, avoiding these losses. In addition,SBSP systems have a longer collection period and the ability to collectsolar energy continuously without the downtime (and cosine losses, forfixed flat-plate collectors) that result from the Earth's rotation awayfrom the sun.

A general limitation for SBSP systems is the size of SPS required togenerate sufficient electrical power from solar energy. For example, fora 500 MW system a 5 km² platform may be required. Such a platform wouldbe formed of large satellites on the order to tens to hundreds oftonnes/satellite. The launch costs associated with placing such largestructures into orbit reduces the economic viability of such SBSPsystems.

SUMMARY

Systems and methods in accordance with various embodiments of theinvention provide a space-based solar power (SBSP) system including aplurality of solar-power satellite modules. In a number of embodiments,the satellite modules include a plurality of modular power generationtiles combining at least one photovoltaic cell, a power transmitter andcircuitry configured to perform a variety of control functions including(but not limited to) coordinating the participation of the powertransmitter in a phased array. Embodiments also provide compactiblestructures, and methods and mechanisms for deploying such compactiblelight weight structures once in a selected operating location. Aplurality of the standalone satellite modules may be collocated, andflown in any suitable orbital formation in space to collectivelyconstitute the space-based solar power system.

Many embodiments are directed to a space-based solar power stationincluding, a plurality of unconnected satellite modules disposed inspace in an orbital array formation, a plurality of power generationtiles disposed on each of the plurality of satellite modules, at leastone photovoltaic cell disposed on each of the power generation tiles, atleast one power transmitter collocated with the at least onephotovoltaic cell on each of the power generation tiles and in signalcommunication therewith such that an electrical current generated by thecollection of solar radiation by the at least one photovoltaic cellpowers the at least one power transmitter, where each of the at leastone power transmitters includes: an antenna, and control electronicsthat controls the phase of a radio frequency power signal that feeds theantenna so that the power transmitter is coordinated with powertransmitters on other power generation tiles to form a phased array.

In other embodiments the satellite modules are disposed in ageosynchronous orbit.

In still other embodiments each of the satellite modules further includea propulsion system incorporating guidance control circuitry thatcontrols the orientation and position of each of the satellite moduleswithin the orbital array formation.

In yet other embodiments each of the power generation tiles furtherincludes one or more position sensors for determining the position ofthe antenna relative to the other antennas of the phased array.

In still yet other embodiments the control electronics receive locationinformation from a reference signal to determine the location of theantenna. In some such embodiments the reference signal is externallygenerated from one of either a global position system or aninternational ground station. In other such embodiments the referencesignal is generated locally on each of the satellite modules. In stillother such embodiments the control electronics utilize the locationinformation from the reference signal to coordinate the phase shift ofthe radio frequency power signal.

In still yet other embodiments the control electronics control the phaseof the radio frequency power signal such that the directionality of theradio-frequency power signal is electronically steerable. In some suchembodiments the phase of the radio frequency power signals of each ofthe power transmitters is coordinated such that the radio frequencypower signals are electronically steerable to one or more powerreceiving rectennas located remotely from the space-based solar powerstation.

In still yet other embodiments the control circuitry further comprises apower amplifier for converting the electrical current to theradio-frequency power signal.

In still yet other embodiments each of the satellite modules are inwireless communication with each of the other satellite modules suchthat at least phase control information is exchanged therebetween.

In still yet other embodiments the photovoltaic cell further comprisesan absorber having a radiation shield disposed on a face thereof ontowhich the solar radiation is incident, and a conductive materialdisposed on an opposite face thereof. In some such embodiments theabsorber is formed from a material selected from the group of silicon,CdTe, and GaInP/GaAs.

In still yet other embodiments the power generation tiles furthercomprise a collector disposed thereon and configured to concentrateincident solar radiation on the photovoltaic cell. In some suchembodiments the collector is selected from the group consisting ofCassegrain, parabolic, nonparabolic, hyperbolic and combinationsthereof.

In still yet other embodiments the power generation tiles furthercomprise a temperature management device configured to control theoperating temperature of the power generation tile. In some suchembodiments the temperature management device comprises a radiative heatsink.

In still yet other embodiments the antenna is selected from the groupconsisting of dipole, helical and patch.

In still yet other embodiments the satellite modules are formed of atleast two movably interrelated elements such that the dimensional extentof the satellite modules in at least one axis is compactible. In somesuch embodiments the movably interrelated elements are foldable relativeto each other by one of the following z-folding, fan-folding, doublez-folding, Miura-ori, and slip-folding. On other such embodiments thefolded movably interrelated elements are further compacted by symmetricwrapping. In still other such embodiments the movably interrelatedelements are prestressed such that a tensional force is distributedthere across. In yet other such embodiments a deployment mechanism isengageable with the at least two movably interrelated elements to applya force thereto such that the elements are moved relative to each otheron application of the force. In still yet other such embodiments thedeployment mechanism comprises one or more elongated booms. In still yetother such embodiments the deployment mechanism comprises weightedelements, and wherein the force is applied by rotating the satellitemodule.

In still yet other embodiments each of the satellite modules are formedof a plurality of movably interrelated elements, and wherein the movablyinterrelated elements are slip-wrapped to reduce the dimensional extentof the satellite module along at least two axes. In some suchembodiments each of the plurality of movably interrelated elements isinterconnected with each adjacent of the plurality of movableinterrelated elements by a slip-fold, and wherein the edges of theplurality of movably interrelated elements are continuouslyinterconnected.

In still yet other embodiments each of the plurality of power generationtiles are formed of a plurality of movably interrelated elements suchthat at least the photovoltaic cell and power transmitter of each powergeneration tile are movable relative to each other such that thedimensional extent of the power generation tiles are reducible along atleast one axis. In some such embodiments the movably interrelatedelements of the power generation tiles are interconnected through one ormore resilient members.

The features and advantages described in the specification are not allinclusive and, in particular, many additional features and advantageswill be apparent to one of ordinary skill in the art in view of thedrawings, specification, and claims. Moreover, it should be noted thatthe language used in the specification has been principally selected forreadability and instructional purposes, and may not have been selectedto delineate or circumscribe the inventive subject matter.

BRIEF DESCRIPTION OF DRAWINGS

The description will be more fully understood with reference to thefollowing figures and data graphs, which are presented as variousembodiments of the disclosure and should not be construed as a completerecitation of the scope of the disclosure, wherein:

FIG. 1 conceptually illustrates a large-scale space-based solar powerstation with a plurality of power satellite modules in geosynchronousorbit about the Earth, according to one embodiment.

FIG. 2 conceptually illustrates a large-scale space-based solar powerstation with a plurality of power satellite modules flying in arectangular orbital formation, according to one embodiment.

FIG. 3 conceptually illustrates a large-scale space-based solar powerstation, a satellite module, and a cross-sectional view of a modularpower generation tile, according to one embodiment.

FIG. 4a conceptually illustrates a cross-sectional view of a modularpower generation tile, according to one embodiment.

FIG. 4b conceptually illustrates a cross-sectional view of aphotovoltaic cell, according to one embodiment.

FIG. 4c conceptually illustrates a block-diagram for an integratedcircuit suitable for utilization in a power transmitter forming part ofa power generation tile, according to one embodiment.

FIG. 5 conceptually illustrates an array of power generation tiles inwhich the antenna elements of the power generation tiles are configuredas a phased array, according to one embodiment.

FIG. 6 conceptually illustrates the power density distribution at aground receiver from a transmission of power from a phased array ofantennas on a solar power station, according to embodiments.

FIG. 7 conceptually illustrates dynamic power allocation from alarge-scale space-based solar power system, according to one embodiment.

FIGS. 8a and 8b conceptually illustrate electronic beam steering usingrelative phase offset between elements of a phased array, according toone embodiment.

FIG. 9a conceptually illustrates a large-scale space-based solar powerstation and a compactable satellite module in a deployed configuration,according to embodiments.

FIG. 9b conceptually illustrates a retracted compactable satellitemodule, according to FIG. 9a in a retracted configuration.

FIG. 10 conceptually illustrates a compactable satellite module having abiaxial folding configuration, according to embodiments.

FIG. 11 provides images of the compaction of a membrane using thecompaction technique of FIG. 10.

FIGS. 12a to 12d conceptually illustrate a cross-sectional view of acompactable satellite module having a slip folding and wrappingconfiguration, according to embodiments.

FIG. 13 conceptually illustrates a perspective view of a compactablesatellite module having a slip folding and wrapping configuration,according to embodiments.

FIG. 14 provides images of the compaction of a membrane using thecompaction technique of FIG. 13.

FIG. 15 conceptually illustrates a boom deployment mechanism for acompactable satellite module, according to embodiments.

FIG. 16 conceptually illustrates a spin deployment mechanism for acompactable satellite module, according to embodiments.

DETAILED DESCRIPTION

Turning now to the drawings, large-scale space-based solar power (SBSP)stations in accordance with various embodiments of the invention areillustrated. In many embodiments, the SBSP systems include arrays ofindependent satellite modules each incorporating arrays of independentsolar electric power generation tiles. In several embodiments, the powergeneration tiles are each formed incorporating independent photovoltaiccells, power transmitters, and control circuits. The satellite modulesand power generation tiles may be formed from compactible structuresaccording to some embodiments. Methods for deploying, stabilizing,operating and constructing such large-scale space-based solar powersystems in accordance with a number of embodiments of the invention arealso described.

A large-scale space-based solar power station is a modular space-basedconstruct that can be formed from a plurality of independent satellitemodules placed into orbit within an orbital formation such that theposition of each satellite module relative to each other is known. Eachof the satellite modules can include a plurality of power generationtiles that capture solar radiation as electrical current and use thecurrent to transmit the energy to one or more remote receivers usingpower transmitters. In many instances, the transmissions are generatedusing microwave power transmitters that are coordinated to act as aphased- and/or amplitude array capable of generating a steerable beamand/or focused beam that can be directed toward one or more remotereceivers. In other embodiments, any of a variety of appropriate powertransmission technologies can be utilized including (but not limited to)optical transmitters such as lasers.

Embodiments relate to lightweight space structures used to construct themodular elements of the solar power station. Some lightweight spacestructures are used in the construction of the power generation tilesand/or satellite modules and may incorporate movable elements that allowthe lightweight space structure to be compacted prior to deployment toreduce the area or dimensional length, height and/or width of the powergeneration tiles and/or satellite modules prior to deployment. The spacestructures may be made of any number, size and configuration of movableelements, and the elements may be configured to compact according to anysuitable compacting mechanism or configuration, including one ortwo-dimensional compacting using, among others, z-folding, wrapping,rolling, fan-folding, double z-folding, Miura-ori, slip folding,wrapping, and combinations thereof. Some embodiments of movable elementsare interrelated by hinges, such as, frictionless, latchable, ligament,and slippage hinges, among others. Some embodiments of structures arepre-stressed and/or provided with supportive frameworks to reduceout-of-plane macro- and micro-deformation of the lightweight structures.Structures and modules may include dynamic stabilizing movement (e.g.,spinning) during deployment and/or operation. Deployment mechanisms todeploy the compactible lightweight structures into a deployedoperational state may be incorporated into or associated withembodiments of the lightweight structures. Some deployment mechanismsmay include (but are not limited to) expansive boom arms, centrifugalforce mechanisms such as tip masses or module self-mass, among others.

Large-scale spaced-based solar power stations according to manyembodiments utilize a distributed approach to capture solar radiation,and to use the energy thus captured to operate power transmitters, whichtransmit power to one or more remote receivers (e.g., using laser ormicrowave emissions). The satellite modules of the solar power stationcan be physically independent structures, each comprising an independentarray of power generation tiles. The satellite modules are each placedinto a specified flying formation within an array of such satellitemodules in a suitable orbit about the Earth. The position of each of theindependent satellite modules in space within the orbital arrayformation is controllable via a combination of station-keeping thrustersand controlled forces from absorption, reflection, and emission ofelectromagnetic radiation, as well as guidance controls. Using suchcontrollers each of the independent satellite modules may be positionedand maintained within the controlled orbital array formation relative toeach of the other satellite modules so that each satellite module formsan independent modular element of the large-scale space-based solarpower station. The solar radiation received by each of the powergeneration tiles of each of the independent satellite module is utilizedto generate electricity, which powers one or more power transmitters oneach of the power generation tiles. Collectively, the power transmitterson each of the power generation tiles can be configured as independentelements of a phased and/or amplitude-array.

The power generation tiles and/or satellite modules may also includeseparate electronics to process and exchange timing and controlinformation with other power generation tiles and/or satellite moduleswithin the large-scale space-based solar power station. In manyimplementations, the separate electronics form part of an integratedcircuit that possesses the ability to independently determine a phaseoffset to apply to a reference signal based upon the position of anindividual tile and/or transmitter element. In this way, coordination ofa phased array of antennas can be achieved in a distributed manner.

In embodiments of the distributive approach, different array elements ofthe phased array may be directed to transmit power with differenttransmission characteristics (e.g., phase) to one or more differentremote power receiving collectors (e.g., ground based rectenna). Eachsatellite module of power generation tiles, or combinations of powergenerating tiles across one or more satellite modules, may thus becontrolled to transmit energy to a different power receiving collectorusing the independent control circuitry and associated powertransmitters.

A photovoltaic cell (PV) refers to an individual solar power collectingelement on a power generation tile in a satellite module. The PVincludes any electrical device that converts the energy of lightdirectly into electricity by the photovoltaic effect including elementsmade from polysilicon and monocrystalline silicon, thin film solar cellsthat include amorphous silicon, CdTe and CIGS cells, multijunctioncells, perovskite cells, organic/polymer cells, and various alternativesthereof.

A power transmitter or radiator refers to an individual radiativeelement on a power generation tile in a satellite module and itsassociated control circuitry. A power transmitter can include any devicecapable of converting power in the electrical current generated by thePV to a wireless signal, such as microwave radiation or light, including(but not limited to) a laser, a klystron, a traveling-wave tube, agyrotron, or suitable transistor and/or diode. A power transmitter mayalso include suitable transmissive antennas, such as, dipole, patch,helical or spherical antennas, among others.

A phased array refers to an array of power transmitters in which therelative phases of the respective signals feeding the power transmittersare configured such that the effective radiation pattern of the poweremission of the array is reinforced in a desired emission direction andsuppressed in undesired directions. Phased arrays in accordance withembodiments may be dynamic or fixed, active or passive.

An orbital array formation refers to any size, number or configurationof independent satellite modules being flown in formation at a desiredorbit in space such that the position of the satellite modules relativeto each other is known such that power generation tiles on each of thesatellite modules within the formation serves as an array element in thephased array of the solar power station.

A power generation tile refers to an individual solar power collectingand transmitting element in the phased array of the large-scalespace-based solar power station. In many embodiments a power generationtile is a modular solar radiation collector, converter and transmitterthat collects solar radiation through at least one photovoltaic celldisposed on the tile, and uses the electrical current to provide powerto at least one power transmitter collocated on the same tile thattransmits the converted power to one or more remote power receivingcollectors. Many of the power generation tiles incorporated within aspace-based solar power station include separate control electronicsindependently control the operation of the at least one powertransmitter located on the power generation tile based upon timing,position, and/or control information that may be received from othertiles and/or other modules within the large-scale space-based solarpower station. In this way, the separate control electronics cancoordinate (in a distributed manner) the transmission characteristics ofeach of the power generation tiles form a phased array. Each powergeneration tile may also include other structures such as radiationcollectors for focusing solar radiation on the photovoltaic, thermalradiators for regulating the temperature of the power generation tile,and radiation shielding, among other structures.

A satellite module refers to an array of power generation tilescollocated on a single integral space structure. The space structure ofthe satellite module may be a compactable structure such that the areaoccupied by the structure may be expanded or contracted depending on theconfiguration assumed. The satellite modules may include two or morepower generation tiles. Each power generation tile may include at leastone solar radiation collector and power transmitter. As discussed above,each of the power generation tiles may transmit power and may beindependently controlled to form an array element of one or more phasedarrays formed across the individual satellite module or several suchsatellite modules collectively. Alternatively, each of the powergeneration tiles collocated on a satellite module may be controlledcentrally.

A lightweight space structure refers to integral structures of movablyinterrelated elements used in the construction of the power generationtiles and/or satellite modules that may be configurable between at leastpackaged and deployed positions wherein the area and or dimensions ofthe power generation tiles and/or satellite modules may be reduced orenlarged in at least one direction. The lightweight space structures mayincorporate or be used in conjunction with deployment mechanismsproviding a deploying force for urging the movable elements betweendeployed and compacted configurations.

A large-scale space-based solar power station or simply solar powerstation refers to a collection of satellite modules being flown in anorbital array formation designed to function as one or more phasedarrays. In embodiments the one or more phased arrays may be operated todirect the collected solar radiation to one or more power receivingcollectors.

Transmission characteristics of a power generation tile refer to anycharacteristics or parameters of the power transmitter of the powergeneration tile associated with transmitting the collected solarradiation to a power receiving collector via a far-field emission. Thetransmission characteristics may include, among others, the phase andoperational timing of the power transmitter and the amount of powertransmitted.

Structure of Large-Scale Space-Based Solar Power Station

A large-scale space-based solar power station including a plurality ofsatellite modules positioned in an orbital array formation in ageosynchronous orbit about the Earth in accordance with embodiments ofthe invention is illustrated in FIG. 1. The large-scale space-basedsolar power station 100 includes an array of independent satellitemodules 102. The solar power station 100 is configured by placing aplurality of independent satellite modules 102 into a suitable orbitaltrajectory in an orbital array formation 104, according to oneembodiment. The solar power station 100 may include a plurality of suchsatellite modules 1A through NM. In one embodiment, the satellitemodules 1A through NM are arranged in a grid format as illustrated inFIG. 1. In other embodiments, the satellite modules are arranged in anon-grid format. For example, the satellite modules may be arranged in acircular pattern, zigzagged pattern or scattered pattern. Likewise, theorbit may be either geosynchronous 106, which is typically at analtitude of 35,786 km above the Earth, or low Earth 108, which istypically at an altitude of from 800 to 2000 km above the Earth,depending on the application of the solar power station. As can readilybe appreciated, any orbit appropriate to the requirements of a specificapplication can be utilized by a space-based solar power station inaccordance with various embodiments of the invention.

In embodiments, the satellite modules in the solar power station arespatially separated from each other by a predetermined distance. Byincreasing the spatial separation, the maneuverability of the modules inrelation to each other is simplified. As discussed further below, theseparation and relative orientation of the satellite modules can impactthe ability of the power generation tile on each of the satellitemodules to operate as elements within a phased array. In one embodiment,each satellite module 1A through NM may include its own station keepingand/or maneuvering propulsion system, guidance control, and relatedcircuitry. Specifically, as illustrated in FIG. 2, each of the satellitemodules 102 of the solar power station 100 may include positioningsensors to determine the relative position 110 of the particularsatellite module 1A through NM in relation to the other satellitemodules 1A to NM, and guidance control circuitry and propulsion systemto maintain the satellite module in a desired position within thearbitrary formation 104 of satellite modules during operation of thesolar power station. Positioning sensors in accordance with manyembodiments can include the use of external positioning data from globalpositions system (GPS) satellites or international ground station (IGS)network, as well as onboard devices such as inertial measurement units(e.g., gyroscopes and accelerometers), and combinations thereof. Inseveral embodiments, the positioning sensors can utilize beacons thattransmit information from which relative position can be determined thatare located on the satellite modules and/or additional supportsatellites. The guidance control and propulsion system may likewiseinclude any suitable combination of circuitry and propulsion systemcapable of maintaining each of the satellite modules in formation in thesolar power station array 104. In many embodiments the propulsion systemmay utilize, among others, one or more of chemical rockets, such asbiopropellant, solid-fuel, resistojet rockets, etc., electromagneticthrusters, ion thrusters, electrothermal thrusters, solar sails, etc.Likewise, each of the satellite modules may also include attitudinal ororientational controls, such as, for example, reaction wheels or controlmoment gyroscopes, among others.

In many embodiments, as illustrated in FIG. 3, each satellite module 1Athrough NM of the solar power station 100 comprises a space structurecomprised of one or more interconnected structural elements 111 havingone or more power generation tiles 112 collocated thereon. Specifically,each of the satellite modules 1A through NM is associated with an arrayof power generation tiles 112 where each of the power generation tilesof the array each independently collect solar radiation and covert it toelectric current. Power transmitters convert the electrical current to awireless power transmission that can be received by a remote powerreceiving station. As discussed above, one or more power transmitters oneach of a set of power generation tiles can be configured as an elementin one or more phased arrays formed by collections of power generationtiles and satellite modules of the overall solar power station. In oneembodiment, the power generation tiles in the satellite module arespatially separated from each other by a predetermined distance. Inother embodiments, the construction of the satellite modules is suchthat the power generation tiles are separated by distances that can varyand the distributed coordination of the power generation tiles to form aphased array involves the control circuitry of individual powertransmitters determining phase offsets based upon the relative positionsof satellite modules and/or individual power generation tiles.

Power generation tiles 112 according to many embodiments include amulticomponent structure including a photovoltaic cell 113, a powertransmitter 114, and accompanying control electronics 115 electricallyinterconnected as required to suit the needs of the power transmissionapplication. As illustrated in FIG. 4a , in some embodimentsphotovoltaic cells 113, may comprise a plurality of individualphotovoltaic elements 116 of a desired solar collection area that may beinterconnected together to produce a desired electrical current outputacross the power generation tile. Some power transmitters 114 includeone or more transmission antennas, which may be of any suitable design,including, among others, dipole, helical and patch. In the illustratedembodiment, a conventional patch antenna 114 incorporating a conductivefeed 117 to conductively interconnect the RF power from the controlelectronics 115 to the antenna 114. As can readily be appreciated thespecific antenna design utilized is largely dependent upon therequirements of a specific application. Some power transmitters 114 arephysically separated from one or both of the photovoltaic cell 113and/or the control electronics 115 such as by fixed or deployable spacerstructures 118 disposed therebetween. Some control electronics 115 mayinclude one or more integrated circuits 119 that may control some aspectof the power conversion (e.g., to a power emission such as collimatedlight or an radio frequency (RF) emission such as microwave radiation),movement and/or orientation of the satellite module, inter- andintra-satellite module communications, and transmission characteristicsof the power generation tile and/or satellite module. Further conductiveinterconnections 120 may connect the control electronics 115 to thesource power of the photovoltaic cell 113. Each of the power generationtiles may also include thermal radiators to control the operatingtemperature of each of the power generation tiles.

In some embodiments, the PV 113 is a multi-layer cell, as illustrated inFIG. 4b , incorporating at least an absorber material 113′ having one ormore junctions 113″ disposed between a back contact 121 on a back sideof the absorber material and a top radiation shield 122 disposed on thesurface of the absorber material in the direction of the incident solarradiation. The PV may include any electrical device that converts theenergy of light directly into electricity by the photovoltaic effectincluding elements made from polysilicon and monocrystalline silicon,thin film solar cells that include amorphous silicon, CdTe and CIGScells, multijunction cells, perovskite cells, organic/polymer cells, andvarious alternatives thereof. In some embodiments the made from a thinfilm of GaInP/GaAs that is matched to the solar spectrum. Radiationshielding may include a solar radiation transparent material such asSiO₂, among others. The back contact may be made of any suitableconductive material such as a conductive material like aluminum, amongothers. The thickness of the back contact and top radiation shield maybe of any thickness suitable to provide radiation shielding to the PV.Additional structures may be provided around the PV to increase theefficiency of the absorption and operation of the device including, forexample, one or more concentrators that gather and focus incoming solarradiation on the PV, such as a Cassegrain, parabolic, nonparabolic,hyperbolic geometries or combinations thereof. The PV may alsoincorporate a temperature management device, such as a radiative heatsink. In some embodiments the temperature management device isintegrated with the control electronics and may be configured to controlthe operating temperature of the PV within a range of from ˜150 to 300K.

In a number of embodiments, the power transmitters that are componentsof power generation tiles are implemented using a combination of controlcircuitry and one or more antennas. The control circuitry can providethe power generation tile with the computational capacity to determinethe location of the power generation tile antenna(s) relative to otherantennas within the satellite module and/or the solar power station. Ascan readily be appreciated, the relative phase of each element within aphased array is determined based upon the location of the element and adesired beam direction and/or focal point location. The controlcircuitry on each power generation tile can determine an appropriatephased offset to apply to a reference signal using a determined locationof the power generation tile antenna(s) and beam-steering information.In certain embodiments, the control circuitry receives positioninformation for the satellite module and utilizes the positioninformation to determine the location of the power generation tileantenna(s) and determine a phase offset to apply to a reference signal.In other embodiments, a central processor within a satellite module candetermine the locations of antennas on power generation tiles and/orphase offsets to apply and provides the location and/or phase offsetinformation to individual power generation tiles.

In many embodiments, the positional information of each tile is receivedfrom partially redundant systems, such as, but not limited to,gyroscopes, accelerometers, electronic ranging radar, electronicpositioning systems, phase and/or timing information from beacons, aswell as employing a priori knowledge from system steering and flightcontrol commands. In several embodiments, electronic systems are locatedon the ground, and/or in space on satellites deployed for this purpose(and, possibly, other purposes, e.g. in the case of using GPSsatellites).

In a number of embodiments, position information may be relayed in ahierarchical fashion between modules, panels and/or tiles within thespace-based solar power station, such that a central processing unitrelays positional information such as location and orientation of theentire space-based solar power station with respect to a ground stationand/or other suitable known locations to modules within the system. Therelayed information can be expressed as an absolute and/or differentiallocation(s), and/or orientation(s) as appropriate to the requirements ofspecific applications. In a similar fashion, the location and/ororientation of each module with respect to the center of the space-basedsolar power station or other suitable reference point can be determinedat each module using processes similar to those outlined above.Furthermore, going down a hierarchical level, the position andorientation information of individual panels and tiles can be determinedin a similar fashion. The entirety or any useful part of thisinformation can be used at the tile-level, the panel-level, themodule-level, the system-level and/or any combination thereof to controlthe phase and/or amplitude of each tile radiator to form a beam or focalspot on the ground. The aggregate computational power of thecomputational resources of each tile, panel and/or module can beutilized since each tile (and/or panel or module) can utilize its localcomputational power available from a DSP, microcontroller or othersuitable computational resource to control its operation such that thesystem in aggregate generates the desired or close-to desired beamand/or focused transmission.

In various embodiments, as illustrated conceptually in FIG. 4c , powergeneration tile control circuitry can be implemented using one or moreintegrated circuits. An integrated circuit 123 can include aninput/output interface 124 via which a digital signal processing block125 can send and receive information to communicate with other elementsof a satellite module, which typically includes a processor and/ormemory configured by a control application. In certain embodiments, thedigital signal processing block 125 receives location information (seediscussion above) that can be utilized to determine the location of oneor more antennas. In many embodiments, the location information caninclude a fixed location and/or one or more relative locations withrespect to a reference point. The digital signal processing block canutilize the received location information and/or additional informationobtained from any of a variety of sensors including (but not limited to)temperature sensors, accelerometers, and/or gyroscopes to determine theposition of one or more antennas. Based upon the determined positions ofthe one or more antennas, the digital signal processing block 125 candetermine a phase offset to apply to a reference signal 126 used togenerate the RF signal fed to a specific antenna. In the illustratedembodiment, the integrated circuit 500 receives a reference signal 126,which is provided to an RF synthesizer 127 to generate an RF signalhaving a desired frequency. The RF signal generated by the RFsynthesizer 127 is provided to one or more phase offset devices 128,which are configured to controllably phase shift the RF signal receivedfrom the RF synthesizer. The digital signal processing block 125 cangenerate control signals that are provided to the phase offset device(s)128 to introduce the appropriate phase shifts based upon the determinedlocation(s) of the one or more antennas. In many embodiments, theamplitude of the generated signal can be modulated and/or varied aloneor in conjunction with the phase appropriately upon the determinedlocations to form the power beam and/or focused transmission. Theamplitude can be modulated in variety of ways such as at the input of apower amplifier chain via a mixer or within an amplifier via its supplyvoltage, an internal gate or cascade biasing voltage. As can readily beappreciated, any of a variety of techniques appropriate to therequirements of a specific application can be utilized to amplitudemodulate an RF signal in accordance with various embodiments of theinvention. The phase shifted RF signals can then be provided to a seriesof amplifiers that includes a power amplifier 129. While the entirecircuit is powered by the electric current generated by the PVcomponent(s) of the power generation tile, the power amplifier isprimarily responsible for converting the DC electric current into RFpower that is transmitted via the RF signal. Accordingly, the poweramplifier increases the amplitude of the received phase shifted RFsignal and the amplified and phase shifted RF signal is provided to anoutput RF feed 130 connected to an antenna. In many embodiments, the RFsignal generated by the RF synthesizer is provided to an amplifier 131and distributed to the control circuitry of other tiles. Thedistribution of reference signals between tiles in a module inaccordance with various embodiments of the invention is discussedfurther below.

Although specific integrated circuit implementations are described abovewith reference to FIG. 4c , power generation tile control circuitry canbe implemented using any of a variety of integrated circuits andcomputing platforms in accordance with various embodiments. Furthermore,satellite modules can be implemented without providing computationalcapabilities on each power generation tile and/or without utilizing thecomputational capabilities of a power generation tile to determinelocations and/or phase shifts for the purposes of generating an RFsignal to feed a power generation tile antenna.

In many embodiments, as illustrated conceptually in FIG. 5, a pluralityof power generation tiles 112 on each satellite module may each form apanel 160 of a modular phased array 162 incorporating at leastself-contained, collocated photovoltaics, power transmitters and controlelectronics within each power generation tile. The control electronicsmay allow for wire or wireless communications between the individualpower generation tiles for the exchange of timing and controlinformation. The array of control electronics may also allow for theexchange of control and timing formation with other satellite modules.Collocation of at least the power collection, far-field conversion, andtransmission elements on each modular power generation tile allows forthe each power generation tile to operate as an independent element ofthe phased array without inter- and intra- module power wiring.

In one embodiment, the power generation tiles and/or satellite modulesmay include other related circuitry. The other circuitry may include,among others, circuitry to control transmission characteristics of thepower generation tiles, thermal management, inter or intra-modulecommunications, and sensors to sense physical parameters, such asorientation, position, etc. The control circuitry may controltransmission parameters such as phase and timing information such thatthe arrays of power generation tiles across each module and across thesolar power station may be operated as independent array elements of oneor more phased arrays. The sensors may include gyroscopes, GPS or IGSdevices to estimate position and orientation, and thermocouples toestimate the temperature on the power generation tiles.

In one embodiment, the circuits for controlling transmissioncharacteristic parameters may be collocated on the several powergeneration tiles or satellite modules and may control each transmitterof each power generation tile independently or in a synchronized mannersuch that the tiles operate as one or more element of one or more phasedarrays. Reference signals (e.g., phase and timing) that can be used tosynchronize the operation of the power generation tiles as a phasedarray may be generated locally on each power generation tile orsatellite module and propagated via wired or wireless intra andinter-module communications links, or may be generated centrally from asingle source on a single satellite module and propagated via wired orwireless intra and/or inter-module communications links across each ofthe satellite modules and power generation tiles. In addition, one ormultiple timing reference signals may be generated from outside thespace-based solar power station system such as one or more satellitesflying in close proximity or even in different orbits; as well as fromone or more ground stations.

Each power generation tile or satellite module may be operatedindependently or collectively as an element in a phased array. Entire ormost operations associated with each individual power generation tilemay be collocated on each of the power generation tiles or collectivizedwithin the satellite module on which the power generation tiles arecollocated, or across multiple satellite modules. In one embodiment, acentral reference signal is generated and deviation (e.g., phase) fromsuch reference signal is determined for each power generation tile arrayelement of the phased array. By propagating a central reference signalfrom the reference signal, higher levels of control abstraction can beachieved to facilitate simpler programming for many operations of thephased array.

In some embodiments, each power generation tile of each satellite modulemay be the same or different. The number of distinct combinations ofphotovoltaic cells, transmission modules and control electronics may beas large as the number of power generation tiles in the satellitemodules. Further, even where each of the power generation tiles on asatellite module are the same, each of the satellite modules 1A throughNM or a group of satellite modules may have different solar radiationcollection or transmission characteristics or may have arrays of powergeneration tiles of different sizes, shapes and configurations.

In embodiments, the solar power station is designed as a modular phasedarray where the plurality of satellite modules and power generatingtiles located thereon form the array elements of the phased array. Forthis purpose, each of the satellite modules may be designed to bephysically compatible with conventional launch vehicles although theachieved power generation of the phased array of the solar power stationmay exceed conventional space-based solar power satellites in manyrespects. Taking advantage of the increased performance, the solar powerstation phased array of the embodiment may include smaller payload sizeand overall array size to obtain equal or better power generationcompared to conventional space-based solar power satellites.Alternatively, the size of the overall solar power station may bereduced compared to solar platforms in conventional solar powersatellites while achieving comparable results.

In order to match the power generation of a conventional solar powersatellite without increasing platform size or weight, the powercollection, transmission and control logic for the individual powergeneration tiles is preferably collocated within each of the powergeneration tiles or within the satellite module on which the powergeneration tiles are collocated thus eliminating the need for intra- orinter-module communications, wiring or structural interconnection. Inone embodiment, much of the power transmission control logic is a singlecollection of functions common to all or most of the power generatingtiles. In this embodiment, the conventional external intra- and inter-power generation tile infrastructure for the solar power station may beentirely eliminated thus reducing the power generated per weight unit(W/kg).

In one embodiment, the phased array of the solar power station includingthe satellite modules and power generation tiles replaces a conventionalmonolithic solar power satellite. The solar power stations includes N×Nsatellite modules, each module including power generation tiles of

$\frac{M}{N^{2}}.$

Table 1 lists example configurations of solar power stations accordingto embodiments replacing conventional solar power stations.

TABLE 1 SPS Configuration Parameters SPS Exemplary Phased ArrayEfficiency Standards Configuration W/kg Max Size System Performance*Solar Cell 35% Efficiency DC-Microwave 78% USEF 41 100 × 95 m PowerReceived 12 GW Conversion Collection 86% JAXA 98 3.5 km PowerReceived/Module 1.72 MW Efficiency Transmission 77% ESA 132 15 km PowerReceived Rectenna 1.34 GW Efficiency Atmospheric <2% Alpha 33 6 kmRectenna size: 6.65 km Absorption Overall 14% Modular Phased 2270 60 ×60 m Total mass 900000 kg Array According (avg: 100 g/m²) to Embodiments*Assuming a Solar Power Station having a 50 × 50 array of 60 × 60 msatellite modules in a geosynchronous orbit with a 1 GHz powertransmission having a a/λ = 0.5, and a solar irradiance of 1400 W/m².

The Conventional SPS performance in Table 1 are taken from publishedliterature. The Exemplary Phased Array System Performance in Table 1 areestimates and may differ based on the actual design parametersimplemented.

The number of power generation tile array elements in each satellitemodule, and the number of satellite modules in the solar power stationmay be determined based on, among other factors, power requirements,payload restrictions, etc. A first factor for the size of an overallsolar power station is the power to be generated at the power receivingrectenna. As illustrated in FIG. 6, in embodiments the power incident onthe ground using a far-field RF emission can have a maximum power lobe(u_(max)) that is dependent on factors including (but not limited to)the size of the array, the wavelength of the RF transmission, and thephase offset error tolerated within the phased array. For example, inembodiments of a 50×50 array of satellite modules in a solar powerstation formed by 60×60 m satellite modules a maximum power lobe of 926W/m² is estimated to be generate on the ground with a sidelobe level of44 W/m². The incident area of the maximum power lobe with a 1 GHzemission is estimated to have a diameter of 6.6 km, while the incidentarea is estimated to have a diameter of 2.8 km for a 2.4 GHz emission.From a power transmission point of view, the preferred number ofelements in the phased array formed by a solar power station and thewavelength of the transmission will depend on the size of the receivingrectenna and/or array of receiving rectennas. In many embodiments it isdesirable to have the maximum power lobe on the ground coextensive withthe rectenna area.

In embodiments this limitation many also be overcome by dividing thepower transmission output 176 of the solar power station 174 betweendifferent rectenna power receivers 178, as illustrated conceptually inFIG. 7. In many embodiments, different collections of elements (e.g.,satellite modules and/or power generation tiles) forming part of thesolar power station 174 may be configured into different phased arraysthat may be simultaneously directed at different rectenna powerreceivers 178 on the ground thus potentially reducing the individualincident areas radiated by the solar power station. In some embodimentsadditional control circuitry is provided either within the satellitemodule or within each of the power generation tiles to allow for dynamicelectronic steering of the transmission beam, either from the collectivepower generation tiles of a satellite module or from each powergeneration tile independently. In some embodiments the power steeringcircuitry may allow for the control of the relative timing (phase) ofthe various power transmitters on the power generation tile arrayelements, as illustrated conceptually in FIGS. 8a and 8b , such thateach transmission beam may be redirected electronically at micro- and/ornano-second time scales. The power transmission from such dynamicallysteerable phased array on a solar power station allows for the entirephased array or portions thereof to be dynamically redirected indifferent directions dependent on demand at one or more rectenna powerreceivers. Embodiments of such dynamically directable phased arrays onpower solar stations, may be used to redirect the power transmission indifferent directions at micro and nano-second time scales by electronicsteering. Embodiments also allow for power transmissions to bedynamically distributed to various ground stations either simultaneouslyor sequentially based on instantaneous local demand. Power levels ateach of such rectenna receivers may also be dynamically adjusted. Rapidtime domain switching of power amongst rectenna receivers can also beused to control duty cycle and alleviate large scale AC synchronizationissues with respect to an overall power grid.

A second factor that may constrain the number of array elements in anysatellite module is the issue of payload size and weight. Currentpayload delivery technologies for geosynchronous orbits range from 2,000to 20,000 kg. Accordingly, the limit to the size of any single satellitemodule is the actual lift capacity of available payload deliveryvehicles. Based on an assumption of 100 g/m² for the phased arraysatellite modules according to embodiments, a 60×60 m satellite modulewould have a weight of 360 kg, well within the limits of currentdelivery technologies. Larger modules could be produced provided theyare within the lift capacity of available lift vehicles.

In some embodiments, satellite modules are compactable such that thesize of the satellite module in one or more dimensions may be reducedduring delivery to overcome payload space constraints and then expandedinto its final operating configuration. As illustrated in FIGS. 9a and9b , in many embodiments the solar power station 180 includes an arrayof satellite modules 182, each satellite module comprising a pluralityof structural elements 184 that are movably interconnected such that theplurality of structural elements may be moved between at least twoconfigurations: a deployed configuration (FIG. 9a ) and a compactedconfiguration (9 b), such that the ratio of the packaged volume to thematerial volume is larger in the deployed configuration when compared tothe compacted or packaged configuration. In embodiments, the structuralelements 184 may be hinged, tessellated, folded or otherwiseinterconnected 186 such that the structural elements can move inrelation to each other between the compacted and deployedconfigurations. Each satellite module of a solar power station may beconfigured to compact to the same or different sizes. In addition,different compacting methods may be used to compact one or moresatellite modules of a solar space station, including, among others, oneand two-dimensional compaction structures. In some embodiments, one or acombination of z-folding, wrapping, rolling, fan-folding, doublez-folding, Miura-ori, slip folding and symmetric wrapping may be used,among others.

In many embodiments the power generation tiles may have furthercompactible and expandable features and structures disposed thereon. Insome embodiments of power generation tiles the photovoltaic cell andpower transmitter may be movably interrelated through a compactablestructure, such that when in a compacted or packaged configuration theelements of the power generating cell are compressed together to occupya total volume lower than when in a deployed configuration. In somedeployed configurations the photovoltaic cell and power transmitter areseparated by a gap (e.g., to create a vertical offset therebetween).Embodiments of compactable structure include motorized interconnectionsand resilient members such as spring or tension arms that are bent orunder compression, among others. Such compactable structures may alsoincorporate packaging techniques such as one or a combination ofz-folding, wrapping, rolling, fan-folding, double z-folding, Miura-ori,slip folding and symmetric wrapping may be used, among others.

The power generation tiles and/or satellite modules may include otherstructures to enhance the collection of solar radiation or transmissionof power from the power generation tiles and/or satellite modules.Embodiments of structures that may be incorporated into power generationtiles and/or satellite modules may include, among others, thermalradiators for controlling the thermal profile of the power generationtiles, light-collecting structures (e.g., radiators, reflectors andcollectors) to enhance the efficiency of solar radiation collection tothe photovoltaic cell, and radiation shielding to protect thephotovoltaic cells, power transmitters and/or control electronics fromspace radiation. Such structures may also be independently compactible,between packaged and deployed configurations, as described above inrelation to other elements of the power generation tiles.

A design for a satellite module or power generation tile may be appliedto different satellite modules or power generation tiles. Othervariables in the solar power station such as spatial distances,photovoltaics, power transmitter, control electronics and combinationswith may be modified to produce a phased array with differing powercollection and transmission characteristics. In this way, a diverse mixof solar power stations may be produced while maintaining the benefitsof the modular solar power station described.

Compactable Space Structures

In many embodiments, the satellite modules of the solar power stationemploy compactible structures. Compactable structures allow for thesatellite modules and/or power generation tiles to be packaged in acompacted form such that the volume occupied by the satellite moduleand/or power generation tiles can be reduced along at least dimension toallow for the satellite modules to fit within an assigned payloadenvelope within a delivery vehicle. Several exemplary embodiments ofpossible packaging schemes are provided, however, it should beunderstood that the packaging procedure and compactible structures mayinvolve, among other procedures, using one and two-dimensionalcompaction techniques, including, one or a combination of z-folding,wrapping, rolling, fan-folding, double z-folding, Miura-ori, starfolding, slip folding and wrapping.

In many embodiments a two-dimensional compacting technique may beutilized to package and deploy the satellite modules and/or powergeneration tiles. FIG. 10 provides a perspective view of a satellitemodule 290 with a plurality of power generation tiles 292, according toembodiments. The plurality of power generation tiles 292 in thisembodiment are hinged together and tessellated into a Miura-ori foldingpattern such that the satellite module is compacted biaxially along an Xand Y axis. Although the hinges interconnecting the panels may be madeof any suitable design, in one embodiment the hinged elements areinterconnected by carbon fiber rods or other suitable support structure.Images of a membrane being folded in accordance with these embodimentsare provided in FIG. 11.

In many embodiments a slip-wrapping compacting technique may be utilizedto package and deploy the satellite modules and/or power generationtiles. FIGS. 12a to 12d provide cross-sectional views of theconstruction of embodiments of the slip-wrapping technique. As shown, inthese embodiments two elongated elements 300 and 302 interconnected at afirst end 304 and open at a second end 306 (FIG. 12a ) are wrapped abouta hub (FIG. 12b ). Such wrapping causes one of the elongated elements300 to slip along its longitudinal length with respect to the secondelongated element 302 such that a gap 308 forms between the unconnectedends of the elements. A second set of such elongated elements 310 and312 interconnected at one end 314 are then obtained by a 180° rotationof the first set of elongated elements and the non-interconnected endsare then joined together 316 to form a single elongated element of anundulating configuration 318 interconnected at both ends 304 and 314(FIG. 12c ). The undulating strip thus formed may then be wrapped abouta hub of a specified radius 320 that is no smaller than the minimum bendradius of the material of the elongated element thus reducing thedimensions of the satellite module biaxially in both an X and a Y axis(FIG. 12d ).

Embodiments of a slip-wrap packing technique as applied to a compactiblesatellite module 350 are shown in a perspective view in FIG. 13. In oneembodiment the satellite module is formed of a plurality of elongatedstructures 352 that are interconnected at two ends 354 and 356, but thatare allowed to shear along their edges. During packaging the elongatedstructures are first folded with z-fold to form an elongated pluralityof structures that are compacted along a first axis 358 orthogonal tothe longitudinal axis 360 of the elongated structures. The compactedelongated structures are then wrapped about a hub with a radius 362(which is selected to be no smaller than the minimum bend radius of theelongated structures of the satellite module) to further compact thestrips along a second axis, thereby forming a fully compacted satellitemodule. Although a satellite module with an overall rectangularconfiguration are shown in FIGS. 12 and 13, it should be understood thatthe technique may be implemented with any configuration, number or shapeof individual strip elements so long as they are joined at the edges andthe edges are permitted to shear as described above. Images of acompactible structure using a diagonal z-fold in accordance with theseembodiments are provided in FIG. 14. In this embodiment the deployedsquare of 0.5 m may be packaged into a cylindrical structure with adiameter of 10 cm and a height of 7 cm.

Using such techniques it is possible to significantly reduce thepackaging volume of the satellite modules. In one exemplary embodimentwhere the compactible structures of a satellite module have a tile/panelthickness of 1 cm and a minimum bend radius of 10 cm, a satellite modulewith a deployed area of 60 m×60 m and being comprised of 30 suchcompactible structures would be compactible using the slip-wrappackaging technique into cylindrical package with a diameter of 5 m anda height of 2 m.

In many embodiments the number of compactible elements in each of thesatellite modules in a solar space station may be the same or differentand may contain one or more power generation tiles collocated thereon.One or more compacting techniques may be used in packaging thecompactible elements of each of the satellite modules and the techniquesuse may also the same or different. In many embodiments the compactingtechniques utilized to package the satellite modules prior to deploymentreduce the packaging volume of the satellite module in at least onedimension such that the satellite module fits within the allowed payloadvolume of the selected delivery vehicle.

In many embodiments the power generation tiles may have furthercompactible and expandable features and structures disposed thereon. Insome embodiments of power generation tiles the photovoltaic cell andpower transmitter may be movably interrelated through a compactablestructure, such that when in a compacted or packaged configuration theelements of the power generation tile are compressed together to occupya total volume lower than when in a deployed configuration. In somedeployed configurations the photovoltaic cell and power transmitter areseparated by a gap (e.g., to create a vertical offset therebetween).Embodiments of compactable structure include motorized interconnectionsand resilient members such as spring or tension arms that are bent orunder compression, among others. Such compactable structures may alsoincorporate packaging techniques such as one or a combination ofz-folding, wrapping, rolling, fan-folding, double z-folding, Miura-ori,slip folding and symmetric wrapping may be used, among others.

In many embodiments deployment mechanisms are provided to deploy thecompacted satellite modules (e.g., move the compactible elements of thesatellite module from a compacted to a deployed configuration). In manyembodiments an active or passive mechanism is interconnected with one ormore portions of the compactible structures of the satellite module suchthat when activated the compacted structures of the satellite modulesmay be expanded into a deployed operational configuration.

In some embodiments a mechanically expandable member may be incorporatedinto the satellite module. An illustration of such a satellite module isprovided in FIG. 15 where a satellite module 400 having a plurality ofcompactible structures 402 are disposed about a central hub 404. Thecompactible structures 402 are interconnected on at least one edge witha mechanically expandable member 406 such that as the mechanical memberis urged outward the compactible structures are also expanded outwardfrom the central hub. The expandable member may be motorized or may usestored energy, such as, compressed or bent expandable members, amongothers.

In many embodiments the compactible structures of the satellite modulemay be configured such that motion of the satellite module provides theexpansive deployable force. An illustration of one such embodiment isprovided in FIG. 16 where weighted elements 420 are attached between acentral hub 422 and at least a portion of each of the compactiblestructures 424 of the satellite module 426 such that when the centralhub of the satellite module is spun the centrifugal force of thespinning hub causes the weighted elements to move outward therebyexpanding the compactible structures. In such embodiments the satellitemodule may be made to spin continuously to provide a stabilization forceto the compactible structures.

Regardless of the mechanism chosen, in many embodiments the satellitemodule may be divided into any number and configuration of separatecompactible structures with any number of hubs and deployment mechanisms(e.g., expandable members, weighted elements, etc.). In many embodimentsthe compactible structures are attached along at least two edges to morethan one deployment mechanism such that more even expansion of thecompactible structures may be obtained. In many embodiments, forexample, multiple weights or expandable members may be attached to eachof the compactible structures along multiple points or edges of thecompactible structures. Some expandable members or weighted elements maybe incorporated into the structure of the compactible structures. Manyembodiments of deployment mechanisms may include deployment controls tocontrollably operate the compactible structures of the satellite modulesso that the satellite modules are expanded into a deployed configurationwhen desired. Some embodiments of such deployment controls may beautomated, such that the positioning or motion of the satellite hubautomatically engages the deployment mechanism, such as, for example, byspinning the satellite module at a specified rate. Other embodiments mayincorporate control circuits such that an external signal or command isrequired to activate the deployment mechanism. Such deployment controlsmay operate across an entire satellite module, may be disposedindividually in each power generation tile, or a combination thereof.

While particular embodiments and applications of the present inventionhave been illustrated and described herein, it is to be understood thatthe invention is not limited to the precise construction and componentsdisclosed herein and that various modifications, changes, and variationsmay be made in the arrangement, operation, and details of the methodsand apparatuses of the present invention without departing from thespirit and scope of the invention as it is defined in the appendedclaims.

What is claimed is:
 1. A space-based solar power station comprising: a plurality of unconnected satellite modules disposed in space in an orbital array formation; a plurality of power generation tiles disposed on each of the plurality of satellite modules; at least one photovoltaic cell disposed on each of the power generation tiles; at least one power transmitter collocated with the at least one photovoltaic cell on each of the power generation tiles and in signal communication therewith such that an electrical current generated by the collection of solar radiation by the at least one photovoltaic cell powers the at least one power transmitter, where each of the at least one power transmitters comprises: an antenna; and control electronics that controls the phase of a radio frequency power signal that feeds the antenna so that the power transmitter is coordinated with power transmitters on other power generation tiles to form a phased array.
 2. The space-based solar power station of claim 1, wherein satellite modules are disposed in a geosynchronous orbit.
 3. The space-based solar power station of claim 1, wherein each of the satellite modules further comprises a propulsion system incorporating guidance control circuitry that controls at least one of an orientation and a position of each of the satellite modules within the orbital array formation.
 4. The space-based solar power station of claim 1, wherein each of the power generation tiles further comprises one or more position sensors for determining a position of the antenna relative to the other antennas of the phased array.
 5. The space-based solar power station of claim 1, wherein the control electronics receive location information from a reference signal to determine a location of the antenna.
 6. The space-based solar power station of claim 5, wherein the reference signal is externally generated from one of either a global position system or an international ground station.
 7. The space-based solar power station of claim 5, wherein the reference signal is generated locally on each of the satellite modules.
 8. The space-based solar power station of claim 5, wherein the control electronics utilize the location information from the reference signal to coordinate the phase shift of the radio frequency power signal.
 9. The space-based solar power station of claim 1, wherein the control electronics control the phase of the radio frequency power signal such that the directionality of the radio-frequency power signal is electronically steerable.
 10. The space-based solar power station of claim 9, wherein the phase of the radio frequency power signals of each of the power transmitters is coordinated such that the radio frequency power signals are electronically steerable to one or more power receiving rectennas located remotely from the space-based solar power station.
 11. The space-based solar power station of claim 1, wherein the control circuitry further comprises a power amplifier for converting the electrical current to the radio-frequency power signal.
 12. The space-based solar power station of claim 1, wherein each of the satellite modules are in wireless communication with each of the other satellite modules such that at least phase control information is exchanged therebetween.
 13. The space-based solar power station of claim 1, wherein the photovoltaic cell further comprises an absorber having a radiation shield disposed on a face thereof onto which the solar radiation is incident, and a conductive material disposed on an opposite face thereof.
 14. The space-based solar power station of claim 13, wherein the absorber is formed from a material selected from the group of silicon, CdTe, and GaInP/GaAs.
 15. The space-based solar power station of claim 1, wherein the power generation tiles further comprise a collector disposed thereon and configured to concentrate incident solar radiation on the photovoltaic cell.
 16. The space-based solar power station of claim 15, wherein the collector is selected from the group consisting of Cassegrain, parabolic, nonparabolic, hyperbolic and combinations thereof.
 17. The space-based solar power station of claim 1, wherein the power generation tiles further comprise a temperature management device configured to control the operating temperature of the power generation tile.
 18. The space-based solar power station of claim 17, wherein the temperature management device comprises a radiative heat sink.
 19. The space-based solar power station of claim 1, wherein the antenna is selected from the group consisting of dipole, helical and patch.
 20. The space-based solar power station of claim 1, wherein the satellite modules are formed of at least two movably interrelated elements such that the dimensional extent of the satellite modules in at least one axis is compactible.
 21. The space-based solar power station of claim 20, wherein the movably interrelated elements are foldable relative to each other by one of the following z-folding, fan-folding, double z-folding, Miura-ori, and slip-folding.
 22. The space-based power station of claim 21, wherein the folded movably interrelated elements are further compacted by symmetric wrapping.
 23. The space-based power station of claim 20 wherein the movably interrelated elements are prestressed such that a tensional force is distributed there across.
 24. The space-based power station of claim 20, further comprising a deployment mechanism engageable with the at least two movably interrelated elements to apply a force thereto such that the elements are moved relative to each other on application of the force.
 25. The space-based power station of claim 24, wherein the deployment mechanism comprises one or more elongated booms.
 26. The space-based power station of claim 24, wherein the deployment mechanism comprises weighted elements, and wherein the force is applied by rotating the satellite module.
 27. The space-based solar power station of claim 1, wherein each of the satellite modules are formed of a plurality of movably interrelated elements, and wherein the movably interrelated elements are slip-wrapped to reduce the dimensional extent of the satellite module along at least two axes.
 28. The space-based solar power station of claim 27, wherein each of the plurality of movably interrelated elements are interconnected with each adjacent of the plurality of movable interrelated elements by a slip-fold, and wherein the edges of the plurality of movably interrelated elements are continuously interconnected.
 29. The space-based solar power station of claim 1, wherein each of the plurality of power generation tiles are formed of a plurality of movably interrelated elements such that at least the photovoltaic cell and power transmitter of each power generation tile are movable relative to each other such that the dimensional extent of the power generation tiles are reducible along at least one axis.
 30. The space-based solar power station of claim 29, wherein the movably interrelated elements of the power generation tiles are interconnected through one or more resilient members. 